Public discussions about the incident evoke disbelief that a homeowner could possibly be charged for shooting an intruder.

The shooting comes more than two years after Pennsylvania adopted the "stand-your-ground" or "Castle Doctrine" law. Act 10 of 2011 allows a person to use deadly force in self-defense against an intruder or attacker. It states that people have "a right to remain unmolested within their homes or vehicles" and should not be required "to needlessly retreat in the face of intrusion or attack outside" their homes or vehicles.

The law is specific in its protection of a person who stands his or her ground in a building or vehicle and outside a building or vehicle.

According to the state police account, Shaffer went after Hughes once Hughes ran away from the house. Shaffer caught up with Hughes and shot him when Hughes turned to run.

The elements are present for a stand-your-ground defense, but the timing is off. Shaffer's reported actions conflict with the legal standard:

• Hughes either had to be "in the process" of unlawfully and forcefully entering the house or inside the house after unlawfully and forcefully entering it. According to the police account, a stranger (Hughes) entered Shaffer's home with an assault rifle and ordered the people to a bedroom. Terry "Dread" L. Fulton, 36, fought with Hughes. Both Hughes and Fulton ran from the house.

• Outside the house, Shaffer had the right to use deadly force under Act 10 if he believed that it was "immediately necessary" to protect himself against death or serious bodily injury from an attacker. According to authorities, Shaffer shot Hughes in the back about a half-hour after the attempted robbery.

• Act 10 also requires that a person using deadly force outside a building or vehicle actually see an attacker displaying or using a firearm or a replica of a firearm. Police did not say whether Hughes was armed when he was shot, but mentioned only an assault rifle in their court document.

Joshua Harris, a legal scholar on stand-your-ground laws, told CBS Philly earlier this year that Pennsylvania's law, unlike a similar one in Florida, requires that a person invoking "stand your ground" outside the home must see a deadly weapon and not merely feel threatened.

U.S. Rep. Scott Perry, R-York County, who initially introduced Pennsylvania's Castle Doctrine bill as a state legislator, likewise told The Daily Pennsylvanian in April 2012: "An ironclad provision within the law says that ... the potential assailant must be displaying a firearm or any other weapon readily capable of lethal use."

Perry declined to comment for this story through his deputy chief of staff, Bob Reilly. Reilly said in an email that Perry doesn't comment on ongoing criminal or legal matters.

Perry said in April of 2012 that he spent several years pushing for such an expansion of the Castle Doctrine in Pennsylvania.

"We don't want anybody to second guess their own safety if someone is clearly threatening them," Perry said at the time.

In November 2010, then-Gov. Ed Rendell vetoed a proposed expansion of the Castle Doctrine. The Pennsylvania District Attorneys Association supported that decision.

The bill eventually signed into law contained several changes that district attorneys requested, including the requirement for the attacker to have a gun, a replica of a gun, or "any other weapon readily or apparently capable of lethal use."

Shaffer related this story to police: He found Hughes's rifle after Hughes fled; Shaffer added some of his own rounds to the rifle; Shaffer went after Hughes with a flashlight and the rifle; Shaffer found Hughes behind the house and told him to freeze; Hughes started to reach into his waistband, and Shaffer thought Hughes was reaching for a gun; when Hughes turned to run, Shaffer fired the rifle at him.

The Castle Doctrine also would not apply if the home intrusion were related to criminal activity in the house. Police have not characterized the activity in Shaffer's home.

"Where a case is pending I don't comment on whether a certain defense will apply," said Richard Long, executive director of the Pennsylvania District Attorneys Association. "The process is still being played out."

Franklin County District Attorney Matt Fogal also declined to comment for this story.